1. Field of the Invention
The present invention relates to a loading apparatus. More particularly, the present invention relates to a disc cartridge loading apparatus for automatically capturing a disc cartridge into a cartridge holder.
2. Background of the Invention
A disc recording and reproducing apparatus including a loading apparatus for automatically capturing a disc cartridge has been proposed by the present applicant in Japanese Patent Application No. 02-281829 as published Japanese Laid-Open Patent No. 04-157660 (JP-A-04-157660). As shown in FIG. 2, the disc cartridge 401 rotatably accommodates an optical disc, a magneto-optical disc or the like and includes an upper half and a lower half. The loading apparatus for automatically capturing the disc cartridge includes, as shown in FIGS. 1 and 2, a cartridge capturing member 404, a cartridge capturing lever 405 and a cartridge capturing operating lever 406. The capturing member 404 has a cartridge capturing pin 403 introduced into and engaged with a recess portion 402 of the disc cartridge 401. The cartridge capturing pin 403 is provided on a distal end of the capturing member 404. The capturing lever 405 supports the capturing member 404 at a distal end portion. The capturing operating lever 406 reciprocatingly operates the capturing lever 405 in the insertion direction of the disc cartridge. The cartridge capturing member 404 is rotatably mounted on the distal end of the capturing lever 405 by a supporting shaft 407. The capturing member 404 is adapted for perpetually biasing the capturing pin 403 in a direction towards the outer lateral side of a cartridge holder 409 as indicated by an arrow a in FIG. 2 by a torsion spring 408. In the ejecting state shown in FIG. 2, the cartridge capturing pin 403 is kept in contact with a pin position controlling tongue 411 under the bias of the torsion spring 408. The pin position controlling tongue 411 is formed by a rim of the opening of a cartridge holding section 401 of the cartridge holder 409. The cartridge capturing lever 405 is engaged with a pair of guide pins 412, 413 formed on an upper plate of the cartridge holder 409 and is reciprocated in the direction of insertion into the cartridge holder 409 for a disc cartridge 401. The cartridge capturing operating lever 406 is formed as a substantially crescent-shaped planner member having its central portion supported for rotation on the upper plate of the cartridge holder 409 about the supporting shaft 414 as the center of rotation. An engaging pin 415 mounted on one end of the capturing operating lever 406 is engaged with an engaging opening 416 of the cartridge capturing lever 405. As a result, when the cartridge capturing operating lever 406 is rotated about the supporting shaft 414 as the center of rotation, the engaging pin 415 is engaged with the cartridge capturing lever 405 and the cartridge capturing lever 405 is reciprocated in the insertion direction of the disc cartridge 401.
The advancing and receding of the cartridge capturing lever 405 is carried out by a tension spring 417 installed between the cartridge holder 409 and the capturing operating lever 406. Before the disc cartridge 401 is inserted into the cartridge holder 409, the tension spring 417 is tensioned by an ejecting plate 418, such that the cartridge capturing lever 405 is positioned at an inserting and ejecting opening of the cartridge holder 409 and the cartridge capturing pin 403 of the cartridge capturing member 404 is rotatably supported at the distal end of the lever 405 and kept in contact with the pin position controlling tongue 411. When ejecting plate 418 is unlocked by the disc cartridge inserted into the cartridge holder 409, a holding lever 419 holding the ejecting plate 418 is disengaged from a pin 420 rotationally operating the holding lever 419, and the capturing operating lever 406 is rotated under the force of the tension coil spring 417. As a result, the capturing member 404 is automatically captured in the disc cartridge insertion direction. At this time, cartridge capturing pin 403 is introduced into and engaged with the recess portion 402 of the disc cartridge 401, so that the disc cartridge is automatically captured into the cartridge holder 409.
In the above-described loading apparatus, when the device of the loading apparatus is moved from the ejecting state to the loading state, the cartridge capturing pin 403 capturing the disc cartridge 401 proceeds to capture the disc cartridge 401 into the inside of the cartridge holder 409 under the force of the torsion spring 408, with the capturing pin 403 being kept in contact with the tongue 411 during capturing of the disc cartridge 401. As a result, a capturing force larger than is necessary is exerted during capturing of the disc cartridge 401 due to friction between the cartridge capturing pin 403 and the tongue 411, such that the tension coil spring 417 mounted between the lever 406 and the cartridge holder 409 needs to be increased in its spring force or spring constant. The result is that it becomes difficult to maintain the ejecting plate 418 at the ejecting position against the force of the tension coil spring 417.
For overcoming these problems, it may be contemplated to provide for a lower spring constant of the tension coil spring 408 adapted for biasing the cartridge capturing pin 403 towards the tongue 411 for diminishing the force of friction between the cartridge capturing pin 403 and the tongue 411. However, in such case, it becomes frequently difficult to open a shutter member 422 adapted for closing an opening 421 of the disc cartridge 401 because the shutter member 422 is subject to load fluctuations by reason of a more or less delicate force balance necessary for a normal operation of the shutter member 422.
The tension coil spring 417 for automatically capturing the disc cartridge 401 into the cartridge holder 409 is arranged substantially in parallel with the insertion direction of the disc cartridge 401. In addition, in the above-described disc loading apparatus, a shutter opening mechanism having a shutter opening lever 430 for automatically opening a shutter provided on the disc cartridge 401 and a trigger mechanism for automatically loading the disc cartridge held by the cartridge holder 409 are arranged in the parallel with the tension coil spring 417.
Since the three different mechanisms are arranged in parallel in the traverse direction of the apparatus, limitations are placed on the size of an opening 431 formed on the cartridge holder 409. That is, if limitations are placed on the size of the opening 431, sufficient space for a unit for vertical movement of the magnetic head 432, as viewed from the opening, cannot be assured.
On the other hand, since the tension coil spring 417 is retained by the cartridge capturing operating lever 406 at a position spaced apart from the center of rotation of the cartridge capturing operating lever 406, a retainer 434 for the tension coil spring 417 on the lever 406 is spaced a larger distance from the center of rotation of the lever 406. The result is a larger displacement of the tension coil spring 417 so that the capturing force of the disc cartridge is not constant.